I have been using the Gerber Gator Exchange-A-Blade Saws for years personally and in my kits I sell: http://www.gerbergear.com/index.php/product/id/189

Inexpensive, lightweight and works great.

You can't go wrong with a Silky, the 180 is a good choice: http://www.silkysaws.com/Silky_Saws/Folding-Straight_2/F180-Hand-Saw-180mm-Large-Teeth